Barbara Yaffe, Vancouver Sun

The so-called "Three Amigos" may be just a little less palsy than usual when they convene in Guadalajara, Mexico, on Saturday for the annual North American Leaders' Summit.

The gathering, a ritual since 2005, tends to be an all-smiles-and-handshakes affair that celebrates cosy relations on the continent and sets priorities for trilateral cooperation.

But this year, in the bustling town that's considered Mexico's Silicon Valley, the trio of leaders -- when off-camera -- probably will exchange notes on a few awkward bits of North American business.

U.S. President Barack Obama, attending his first such summit, already has hinted he will withdraw American support for the four-year-old Security and Prosperity Partnership.

The project was aimed at harmonizing North American regulations for business in order to smooth cross-border trade flows.

But in both Canada and the U.S., the SPP, spearheaded by teams of national business leaders, was harshly criticized for its lack of transparency, and portrayed by some as a secret plan to integrate North America.

The SPP been stalled since George W. Bush left office.

A prominent opponent of the SPP, the Council of Canadians, says on its website, "Commentators now acknowledge that public opposition to deep integration talks have made the SPP politically poisonous."

Accordingly, Obama is expected to lead the way in renaming the venture and enlarging its membership to include labour, environmental and human rights groups.

Another topic that probably will be bandied about is the July 14 decision by Canada to impose a visa requirement on Mexican visitors.

The number of Mexicans seeking asylum since 2005 has tripled, translating into heavy costs and delays for Canada's immigration system.

The move, from a continental perspective, is controversial. The Waterloo, Ont.-based Centre for International Governance Innovation, which has leading Canada-U.S. commentators such as political scientists Stephen Clarkson and Chris Sands on its board, says the gesture is considered by some to be "one of the most perplexing, and possibly damaging, foreign policy decisions the government has taken in some time."

It states further that the visa requirement makes Canada's Americas policy look self-interested and "suppresses the sense of a real North American community."

That said, the U.S. has long had a visa requirement for Mexican visitors.

A third controversial issue that has surfaced lately in relation to the continent is whether the U.S. should be treating its northern and southern borders the same, neglecting the fact that dealings with Canada are far less problematic than with Mexico.

A report in July by the Washington, D.C.-based Brookings Institution criticized Homeland Security chief Janet Napolitano's preferred policy of standardizing policies for the two borders.

Beyond these thornier topics, Obama, Stephen Harper and Felipe Calderon are expected to chat about the economy, Buy America legislative provisions, national security and crime, environment and climate change, energy security, measures to deal with the H1N1 virus and the recent coup in Honduras.

The leaders' summits last only a couple of days and have their greatest value in enabling the three nationally preoccupied leaders to become more comfortable with one another and their respective priority issues.

Obama, since becoming president in January, has met once with Harper and several times with Calderon.